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Felice Dunn, PhD

Anatomy and function of retinal circuits under normal and disease states

To restore vision, we must understand how information is processed in the mature retina and how structural and functional organization are affected during degeneration. The divergence of signals at the first synapse in the visual system, where a single cone provides input to 10-12 types of cone bipolar cells, provides a unique opportunity to study the origin of parallel pathways. This synapse also exhibits convergence, where each type of cone bipolar cell receives inputs from a stereotyped number of cones.

Our recent work demonstrates that three types of cone bipolar cells establish their unique patterns of structural contact with presynaptic cone photoreceptors according to different strategies and segregated timelines. However, we know little about how these differences translate into functional properties in the mature circuit. Moreover, how cone bipolar cell types respond to progressive loss of photoreceptors during disease is unclear.

The overall goal of our lab is to understand how visual information is parsed and processed in the retina at the cone-to-cone bipolar synapse and to determine how this information is perturbed in disease. We aim to determine the functional properties of 12 morphologically characterized bipolar cell types and to uncover how these bipolar cells change their structure and function in a degenerating retina. In pursuit of our goals, we will reveal how a bipolar cell’s functional properties are determined by its anatomical connections with cones and will provide an understanding of how bipolar cells respond to photoreceptor degeneration as a model of potential circuit rearrangements in retinal disease.

Current Projects

To determine how cone convergence and divergence shape the functional properties of different bipolar cell types.

To identify the effects of cone degeneration on bipolar cell structure, connectivity, and function.